I think one of the biggest issues with Ikeme last season - because we know he *can* be capable at this level - was that he had essentially zero meaningful competition from November onwards. Martinez was injured and then we decided that we weren't going to sign him (too expensive post-Morgan putting the club up for sale I bet) so unless Ikeme got injured we weren't going to pick him, what would be the point when we weren't going anywhere and there was no chance of him being here after May. This meant it didn't matter how many crap goals he gave away - and there were plenty - because there wasn't any consequence to it, it seems to have got to him to the point that he's deluding himself now that he had a good season.
If you go and sign someone of Cropper's standard, someone you're never going to pick unless you have to, it's the same situation. Hurts the team as well because in practically every other position you can take someone out for a while if they're playing so poorly as to be detrimental to the team, which is what Ikeme was at points last season.
As I said a few weeks ago, I'm happy to write last season off, accept that he's had two good seasons before that and give Ikeme another go as number one - but there must be someone behind him actively pushing him for his place and who we can bring in if we have another repeat of that shambles. It'd be a serious mistake just to bring in a token number two who's happy sitting on the bench and who we're happy to have to do no more than that. That's no way to run a squad, not in our circumstances where we cannot (literally cannot) afford deadwood, everyone who is here should be contributing. It'd also be extremely risky given Ikeme's injury record, he missed at least one full month in all of 2012/13, 2013/14 and 2014/15. Imagine him breaking his foot or something in September and us having a barely L2 standard keeper as our only replacement outwith kids, it'd have the potential to wreck your season in an instant.